Highest quality you can afford.
Depends on your budget.
I have rme802 paired with apogee AD16x.
Rme is transparent but good sounding, Apogee has a little bit of color (i hear a little bit more extanded low end?? Could be placebo?). Maybe new ones sound different. Both mpc3000 and s950 sound killer thru both of them.
akai mpc 3000
akai mpc 60mk1
akai s3000
roland sp 303
roland sp 404sx
roland sp 555
moog subsequent 37
" There is something on every record "